Nitro sulphato azo dyes



Patented Oct. 30, 1945 NITRO SULPHATO AZO DYES Friedrich Felix, Basel, Switzerland, and Werner Ziircher, deceased, late of Basel, Switzerland, by Josef Ziircher, administrator, Horgen, Switzerland, assignors to Society of Chemical 1ndustry in Basle, Basel, Switzerland No Drawing. Application May 1, 1942, Serial 'No. 441,376. In Switzerland January 5, 1938 6 Claims.

It has been found that new azo-dyestuffs are obtained when monoazo-dyestufls which are free from carboxylic and sulphonic groups and correspond to the general formula in which R1 and R2 represent aromatic nuclei of the benzene series and a: and 11 represent members of the group consisting of hydrogen and alkyl radicals, at least one of these symbols :1: and y standing for a hydroxy-alkyl radical, and in which moreover the radical R1 carries at least once a substituent capable of increasing the acidic properties of an aromatic hydroxyl group, preferably in a position difierent from the orthoposition to the -N=N- group, and in which the atomic grouping -N=N- stands in the paraposition to the atomic grouping are treated in the presence of sulphonating agents (1. e. sulphuric acid, chlorosulphonic acid or sulphuric acid containing $03) with nitrating agents. Substituents capable of increasing the acidic properties of an aromatic, hydroxyl group are for example the'nitro-group, halogens, the cyano-group, derivatives of carboxylic groups and sulphonic groups, such as for example COOCzHs, COCHa, CON(C2H5) 2, SOzNHz,

SO2N(CH3) 2, SO2CH3, SOzCzHs-groups wherein R1 and-Rz stand for nuclei of the benzene series and m and y stand for a member of the group consisting of hydrogen and alkyl radicals, at least one of the symbols :0 and 11 standing for the acid sulphuric acid ester of a hydroxyalkyl radical, wherein furthermore the radical R1 contains in a position different from the ortho-position to the N=- N- group at least once a substituent which increases the acidic properties of an aromatic group, wherein the atomic groups -N=N- and stand in para-position to one another, and wherein the radicals R2 carries a nitro-group.

Among the dyestuffs suited for the process may be mentioned products such as 4-nitro-4'-,8-hydroxyethyl'amino-l:1*-az0benzene, 4 nitro 4'- methylefi-hydroxyethyl amino-1:1-azobenzene, 4-nitro-4'-di-,B-hydroxyethyl amino 1:1'-azobenzene, 4-nitr0-4'-methyl p dihydroxypropylamino-1:1'-azobenzene, 4 nitro 4-butyl-c-hydroxyethyl amino 1: l-azobenzene; further 4- nitro-4- ,8-hydroxyethy1amino 5'-methyl 1:1- azobenzene, 4 nitro-4'-ethyl B hydroxyethylamino-5'-methoxy-1:l-azobenzene, 3 nitro 4'- p-hydroxyethylamino-l 1-azobenzene, 3 nitro 4'-ethyl-5-hydroxyethylamino 1: 1' -azobenzene, 3-nitro-4'-ethyl 13 hydroxyethyl amino 5 methyl-1:1'-azobenzene, 3 nitro-4'- ethyl-B-hy droxyethylamino-5-methoxy '1: 1' azobenzene, 3-'nitro-4-methy1 ,9 hydroxyethylamino 1: 1'- azobenzene, 3 nitro 4'- B -hydroxyethyl-butyl amino-1:1'-azobenzene, 2 nitro 4'-arnino-4-chydroxyethyl-amino-l 1'-azobenzene, 2-nitro-4'- methyl-,8 hydroxyethylamino l:1-azobenzene, Z-nitro- L'-fl-hydroxyethylamino 6' -chloro-1 1 azcbenzene, 4 chloro 4"-y3-hydroxyethylamino- 1: 1-azobenzene, 4 bromo 4'43 'hydroxyethylamino-1:1'-azobenzene, 3 chloro 4'- methyl-5- hydroxyethylamino-l l-azobenzene, 2-chloro-4 butyl-p hydroxyethylamino-l: l'-azobenzene, 4- sulphonmethyl 4'--;3 hydroxyethylamino 1:1- azobenzene, 2 sulphonmethyl 4-methy1-fi-hy droxyethylamino 1:1'- azobenzene, 3 sulphonic acid-4' p-hydroxyethylamino 1:1'- azobenzene, 4-su1phonic acid 4'- methyl B hydroxyethy1- amino-1 1'- azobenzene, 2: 5-dichloro-4'-methylfi-hydroxyethylamino-lz1 azobenzene, 4-bromo- 4='-methy1- ,B hydroxyethylamino 1:1'-azobenzene, 2:5-dichloro 4'-metbyl B hydroxyethylamino-1: 1'-azobenzene, 4 nitro-2 6-dich1oro-4- methyl-18-hydroxyethylamino l:1- azobenzene, 4-nitro-2:6-dichloroor 2-Ch101'O-6-bIOm0-4'13 dihydroxyethylamino-l:1'-azobenzene, 4 cyano- 4' ,8 hydroxyethylaminc 1:1 azobenzene, 4- cyano-l'-methyl-fl-hydroxyethylamino-1 1' azobenzene, 4-carboxylic acid ethy1amido-4'-fi-hydroxyethylamino- 1:1 -,azobenzene. alkyl group in N-hyd'roxyalkyl-all ylaminoazobenzenes may be substituted, for example by esterified or etherified hydroxyl groups, by cyanogen groups f For instance such com- 1 or by halogen atoms. pounds may be used as 3-nitro-4'-,8-hydroxyethyl methoxyethylamino 1:1 azobenzene, 3- nitro 4'-/8-fl-hydroxyethyl-fi-chloroethylamino- 6'-methyl-1:1- azobenzene, 4 nitro- 4-; cyano ethyl-fl-hydroxyethylamino -'1:1'- azobenzene, '4- nltro-4'-p-hydroxyethyl-p-chlorethylamino-1 1 azobenzene, 3 nitro-4'-chloromethyl-fi-hydroxyethylamino-l 1'-azobenzene.

These dyestufis are thus treated with nitrating agents in the presence of sulphuric acid or ch10 rosulphonic acid. Owing to the fact that the nitration is effected in the presence of sulphonating agents, the aliphatically boundOH-group of the N-alkyl radical are esterified by the QsOsH-group. The new dyestuffs represent therefore the acid sulphuric acid esters of the dyestuffs of the general formula stands in the para-position to the atomic grouping and in which theradical R2 is substituted in most cases by a nitro group. Particularly valuable are those dyestuffs in which :1: stands for the acid sulphuric acid ester of a hydroxy-alkyl radical, for example a radical of the formula or of the formula -CH2--CH2OSO3H, and in which 1; stands for hydrogen or unsubstituted alkyl radicals.

Among the dyestuffs in which a: and 1; have the above indicated meaning, those are again particularly valuable in which a halogen atom or still better a nitro group exists in the radical R1 in a position which i different from the ortho-position to the radical N=N-. In the form of their alkali salts, the new dyestuffs represent therefore water-soluble yellow to red and brown powders and dye acetate rayon from a neutral aqueous bath in shades of greenish yellow, yellow, orange, brown and red.

The new process permits, among other things, the manufacture of a series of water-soluble aminoazo-dyestuffs of a new type, which maybe used, as mentioned above, to dye acetate rayon, particularly for the dyeing of yellow shades. In.

for acetate rayon-solubility, aflinity, fastness to light and non-phototropic properties-have hitherto been very rare and even unknown. The

new dyestuffs are also valuable for dyeing other products, for example fibers known by the registered trade-mark Nylon.

Thefollowing examples illustrate the invention, the parts, unless otherwise stated, being by weight:

a Example 1 t 2.9 parts of 3 -nitro-4-(fl-hydroxyethyl)-amino-'1:1'-azobenzene of the formula are dissolved by. stirring with 30 parts by volume of concentrated ulphuric acid, and the solution is carefully mixed at 5 to 5 C. with 1.4 parts of a nitrating acid consisting of 0.7 part of nitric acid and 0.7 part of sulphuric acid. Stirring is continued, the temperature allowed to rise to 10 C. and thenitrating mass poured onto ice. There is obtained a viscous suspension of the nitrated. sulphuric acid ester of 3-nitro-4'-(fi-hydroxyethyl) amino-1:1'-azobenzene, which is precipitated by addition of 20 per cent of sodium chloride '(calculated on the volume). stuff is filtered, stirred in about 1500 cc. of water and mixed with so much sodium carbonate solution of 10 per cent strength that Brilliant paper is just colored red. The solution formed is stirred with 20 per cent of sodium chloride (calculated on the volume of the solution), whereby. the sodium salt of the nitrated sulfuric acid ester of 3-nitro-4- (p-hydroxyethyl) -amino-1 1' -azoben,- zene is precipitated. When dry, the new dyestuff is a red brown powder.

The dyestufi" of the formula CHECHFQH may be treated in similar manner in concentrated sulphuric acid with nitric acid. Further dyestuffs are obtained when treating in similar-manner a dyestuff of the formula Example 2 31.4 parts of 3-nitro-4'-(ethyl-fl-hydroxyethyl) -arnino-1:1'-azobenzene of the formula are dissolved at 0 C. in 350 parts by volume of concentrated sulphuric acid. 14 parts of a solution of '7 parts of nitric acid in 7 parts of sulphuric acid are added in drops at 5 to 5 C. Stirring is The precipitated dyeminted until e 'tmperfififire h s risentdio" C. and the solution is poured on as little'ice as possible. The precipitated dyestuff is filtered,

stirred in about 1500 cc. of water and mixed with M so much sodium carbonate solution of per cent.

strength that Brilliant paper is just colored red.

' The solution formed is stirred with 20 per cent. of

sodium chloride (calculated on the volume of the solution), whereby the, sodium salt of the'nitrated sulphuric acid ester of 3-nitro-4'-(ethyl-p-hy-' (IJHa CHa-CHa-OH N05 or the dyestuff of the formula CHr-CHrOH NO: CH5

in concentrated sulphuric acid.

When dissolving the dyestufl of the formula CHr-CHz-OH NO:

in concentrated sulphuric acid and treating it with nitric acid, there is obtained a product which dissolves in water to a red brown solution and dyes acetate rayon from an aqueous solution red brown shades. Instead of sulphuric acid there may also be used chlorosulphonic acid as solvent or as sulphonating agent.

Example 3 6.3 parts of 4-nitro-4'-(ethyl-p-hydroxyethyl) amino-1:1'-azobenzene of the formula CaHa CHz-CHr-OH are dissolved in 65 parts by volume of sulphuric acid as described in Example 1 and nitrated with 2.8 parts of a mixed acid of equal parts of sulphuric acid and nitric acid. The nitration product which has been poured onto ice is mixed with so much saturated sodium carbonate solution that at the end Brilliant paper is slightly colored red. The sodium salt of the nitrated sulphuric acid ester of 4 nitro-l' (ethyl N hydroxyethyl) amino-1:1-azobenzene which has precipitated, if necessary after addition of sodium chloride, is a dark powder when dry which dissolves completely already in cold water to a red solution.

In some cases a dyestuff may also be treated in a sulphuric acid containing S03, dissolved with nitric acid, or also with a salt thereof, for example potassium nitrate.

Thus the dyestufl. of the formula yields a brown red, when treated in sulphuric acid solution with potassium nitrate.

Example '4 0.5 part of the dyestufi described in the first paragraph of Example 1 is dissolved in 3000 parts of water. This 'dyebath is then mixed with 40 parts of crystallized sodium sulphate and 100 parts of acetate artificial silk yarn are handled therein for one hour at C. After rinsing and drying, the artificial silk has a pure yellow tint.

Depending on the choice of dyestuff, acetate artificial silk can be dyed various tints.

The procedure is similar with the dyestuffs described in the other examples, brown and red shades, respectively, being obtained. Further yellow to brown, orange and red shades are also obtained with the dystufi's obtained by combining the components enumerated in the introduction.

This application is a continuation-in-part of application Serial No. 312,618, filed January 5, 1940.

What is claimed is:

1. A processfor the manufacture of an azodyestuff, which comprises treating with a nitrating agent in presence of a sulphonating agent a monazo-dyestuif which is free from sulphonic and carboxylic groups and corresponds to the formula wherein R1 and R2 stand for nuclei of the benzene series, wherein :1: stands for a member of the group consisting of hydrogen and an unsubstituted alkyl and wherein furthermore the radical R1 contains in a position which is different from the ortho-position to the N=N group one nitro group, and wherein the atomic groupings N=N and hydroxyalkyl stand in para-position to one another.

2. A process for the manufacture of an 9.20-

dyestuff, which comprises treating with a nitrating agent in presence of a sulphonating agent a monoazo-dyestufi of the formula wherein :1: stands for a member of the group consisting of hydrogen and unsubstituted alkyl.

4. The water-soluble products corresponding in the free form to the formula wherein one y stands for a hydrogen atom and the other 1/ for a nitro group, and :1: stands for a. 6; The water-soluble products corresponding member of the group consisting of H, CH3 and in the free form to the formula C2H5.

' 5. The water-soluble products corresponding 7 t in the free form to the formula 5 t N0 CHz-CH2OSO:H

FRIEDRICH FELIX.

Z v wherein :1: stands for a, member of the group con- NO N=N- N v slstmg of H, CH3 and CzHs.

GHa-CHzO-SO3H 1 7 JOSEF Zi'IR/CHIER,

wherein .1: stands for a member of the r p Administrator of the Estate of Werner Zitrcher, sisting of H, CH3 and C2H5. Deceased. 1 

